Underwater glider



NOV- 17, 1964 F. E. FARRls ETAL 3,157,145

UNDERWATER GLIDER lFiled Dec. 7, 1960 3 Sheets-Sheet 2 Z4 4a F765 35 3 a 32 60 bl "lull m INVFNTORS. FRNKLYN E. FARRIS WOODFORD M. RAND n 5y ATTORNEYS Nov. 17, 1964 F. E. FARRIS ETAL 3,157,145

UNDERWATER GLIDER Filed Deo. 7, 1960 3 Sheets-Sheet 5 IN VEN TORS.

FRANKLYN E. FARRIS WOODFORD M. RAND ATTORNEYS United States Patent 3,157,145 UNDERWATER GLIDER Franklyn E. Farris, Candlewood Shores, Brookfield, Conn., and Woodford M. Rand, Stonybrook, N.Y., assignors to Oceanic Systems Corporation, Stonybrook, N.Y., a corporation of Delaware Filed Dec. 7, 1960, Ser. No. 74,276 11 Claims. (Cl. 114-16) The present invention relates to an underwater glider capable of sustained periods of operation underwater, for purposes of accomplishing selected missions, by advantageously employing buoyancy control.

During recent years, it has become increasingly important to obtain data for oceanographic studies of marine life and phenomena. In addition, other underwater missions may be required depending upon the results sought or desired to be obtained. Thus, photographic, as well as other similar equipment may be essential for the intended mission. In some cases, recovery of certain natural products of the sea may be the sole desire or, on the other hand, incident to the particular study being conducted.

However, expense and, in some instances, tactical employment of the underwater glider is of prime importance. For example, noise generated by the craft could be detrimental to the accomplishment of the selected mission. Similarly, for any number of reasons, it may be necessary for the mother vessel to be located an appreciable distance from the general location at which the craft is expected to obtain the desired data and information or merely reach the selected objective or target.

It is, therefore, an object of the present invention to provide an underwater glider which is generated in a forward direction through the use of buoyancy control.

Another object is a hydrodynamic glider capable of carrying an instrumentation payload or the like which will permit the acquisition of data at relatively low costs and, at the same time, at rates and magnitudes significantly superior.

A further object is to provide a hydrodynamic glider of relatively reduced size and which, for all intents and purposes, is silent while traversing the programmed underwater course or trajectory.

An important object is to provide a hydrodynamic glider which is capable of varying glide paths. As a result of provisions for means for selectivity of foil coniiguration, incidence angle, and aspect ratio, optimum hydrodynamic characteristics are present both during ascent and decent.

Another important object is a hydrodynamic glider capable of traveling underwater over a preset course and which, at the same time, incorporates actuating means for controlling buoyancy change in accordance with the encounter or expiration of predetermined conditions; and, furthermore, a glider which is capable of resting upon the ocean floor for a period of time prior to resuming its programmed course or accomplishment of its programmed mission.

Other objects and advantages will become apparent from the following detailed description of the invention, which is to be taken in conjunction with the accompanying drawings in which:

FIG. 1 is a diagrammatic view illustrating a typical rice glide pattern traversed by an operating cycle for a hydrodynamic glider incorporating the teachings of the present invention;

FIG. 2 is a side elevational View of an embodiment of an underwater glider contemplated by this invention;

FIG. 3 is a top plan view of this glider;

FIG. 4 is a front elevational view, thereof;

FIG. 5 is a schematic view illustrating the general layout of components within the hull of the craft for purposes of facilitating the understanding, as well as description of operation of the present invention;

FIG. 6 is an enlarged schematic view, with certain parts broken away and removed, of the vent mechanism which permits the escape of the contained gas so that a negative buoyancy is created;

FIG. 7 is an enlarged schematic view, with certain parts broken away and removed while other parts are shown in section, of the gas release valve for permitting the discharge of gas so that a positive buoyancy is obtained;

FIG. 8 is an enlarged schematic View of a mechanism contemplated by this invention for actuating the foil in response to the change in glide path from ascent to decent and vise versa;

FIG, 9 is a top plan view illustrating schematically further means for alternating the chord of the foils and, at the same time, permitting a change of foil dihedral;

FIG. 10 is a front elevational View based on the embodiment illustrated in FIG. 9 showing a dihedral that may be employed during glider decent with the dihedral for ascent illustrated in phantom;

FIG. 10a is a fragmentary side elevational view of the glider of FIG. 10;

FIG. 11 is a schematic view of a recovery system contemplated by the present invention.

Generally, the present invention will encompass a craft 20 capable of performance underwater, in accordance with a programmed trajectory, by simply providing means for changing the craft buoyancy. Thus, a horizontal component of movement is obtained without requiring the ordinary propelling means conventionally employed by water craft. The craft 20 will be formed with a chamber or ballast compartment 22 adapted to be tilled with water through the operation of vent mechanism 24, to provide a glide pattern in a downward direction. At the same time, this chamber 22 is provided with means including' a gas release valve 26 for enabling the contained water to be displaced with gas suitably located in reservoir 28 also within the craft, when it is desired to obtain ascent or an upward trajectory. As will become evident, the ballast water will be discharged through the venturi 30. Thus, by simply changing the buoyancy of the craft 20 in such manner, in combination with provisions for stability and litt, a downward-then upward, etc-underwater trajectory can be imposed upon the craft 20 while beneath the surface of a body of water bearing in mind that the glider is confined to its glide path essentially by the operation of the principal forces of total lift, total drag and weight.

Obviously, the length of time the craft 20 is capable of following a programmed underwater course will depen-d, for the most part, on the supply of gas upon the craft. Then again, a suitable timer can initiate surfacing of the craft after a preset run or mission has been accomplished.

In this connection, an actuating means 31 is preferably provided on the craft 20 for purposes of changing the craft buoyancy at the desired locations along the glide path. For example, a suitable timer can control the operation of the valve of vent mechanism 24 and gas release valve 26. With this in mind, the craft 20 can sit on the bottom of the water for any length of time for purposes of accomplishing its mission and then rise. On the other hand, a suitable device, such as a switch, can be employed responsive to underwater depth or pressures, as well as other underwater conditions. It is in the nature of the latter that the glide path of the embodiment disclosed herein is programmed by the operation of the actuating means 31.

As will be appreciated, the hydrodynamic glider 20 is capable of extended transit through buoyancy control. A complete transit involving several cycles will be described with particular reference being made to FIG. l.

Thus, the vehicle 20 is launched at location A and assumes a downwardly directed glide path. The vent mechanism 24 will shut at point B located on the path, at a preselected depth. When the selected time interval has expired, or pressure or condition encountered, the gas will be released from reservoir 28 through valve 26 to initiate the ballast blowing at a point prelocated along the trajectory at a depth initially selected or, on the other hand, determinable Within reasonable and practical limits. Vehicle acceleration and pitch-up will be experienced at location D along the glide path. At location E, when the desired parameter has been experienced, the ballast blowing stops and the vehicle 20 will glide upwardly in a controlled manner as illustrated. At such time as the initial preselected depth has been reached during the vehicle ascent, the vent mechanism 24 will open and initiate ballast flooding at point F of the glide path. Vehicle acceleration and pitch-down will now be the case at the apex G of the trajectory. The vent mechanism 24 will once again close when the selected depth has been reached, as indicated at point H of the trajectory, to reinitiate in a controlled manner vehicle descent. When the vehicle 20 has been put through the desired number of cycles of operation, the vent mechanism 24 will be prevented from opening at point I of the trajectory, with the result that the vehicle 20 will surface for recovery at location I.

Referring now to the basic construction contemplated for :the glider 20, it will be noted lthat a hull or shell 32 with a generally streamlined contour is provided having a nose 34 of substantially hemispherical configuration. The venturi 30 is located aft at 36 so that an impulse effect can be created. The desired and selected payload and/or instrumentation 35 may be advantageously located in the nose 34 or, for that matter, anywhere within or on the craft 20 as long as the optimum center of gravity is approached for maximum stability during programmed gliding. The hull 32 may be comprised essentially of a number of frames 38, illustrated schematically in FIG. 5, on which may be placed suitable skin or planking 40, which could be suitably finished or resurfaced with a iber forti'ed polyester resin together or in lieu of a layer of heavy grade cloth. As will be apparent, the shell 32 can be fabricated entirely from a fiber fortified polyester resin, as for example, the well known ber glass materials, or even a light-weight metal, such as aluminum. Provisions should be made for access to compartment 22 through the shell 32 so that the interiorly mounted components can be installed, replaced or repaired, as the case may be.

For purposes of obtaining the desired degree of stability during ascent and descent, a lead ballast 42 may be found to be necessary and may be disposed within the hull 32 as shown. A pair of foils project from the hull 32 intermediate its ends and are suitably shaped and, in addition, dimensioned to provide a component of lift 4 to be described in detail below. A pair of stabilizer fins 48 and 50, as well as a rudder 52 are located aft of the hull 32 and also serve to stabilize the glider 20 during its imposed trajectory.

With respect to the vent mechanism 24 illustrated in FIG. 6, a vent valve 54 may form part of the hull skin 40 and be adapted to provide a hermetic seal therewith through a suitable O-ring 56. A depending valve stem 58 is displaceable with respect to a stem guide 60 suitably secured to the interior of the hull 32. The valve 54 is arranged to open and close through the actuation of a Sylphon bellows 62 through the interposed bell crank 64. As will become evident, the bellows 62 is of a type that is normally biased such that it will tend to assume an expanded condition and collapses when pressure in the ballast compartment exceeds predetermined pressures. The bell crank 64 includes a pair of diverging arms 68 and 70, the connecting corner of which is pivoted to a fixed support by means of a pivot pin 72. The free ends of arms 68 and 70 are pivoted by means of pins 74 and 76, respectively, to the bellows 62 on one hand, and the valve stem 58 on the other. A spring driven ratchet wheel 78 is biased so that it will have a tendency to rotate in a counterclockwise direction as viewed in FIG. 6. As will be observed, the ratchet wheel 78 includes a number of teeth 80, as well as an interrupted periphery 82 for purposes that will become evident shortly. Projections 84 and 86 serve to engage with the teeth of the wheel 78 in a manner simulating that of a Well known pawl.

The glide of the craft 20 will continue according to its operating cycle; and at a point along its path that will be at a predetermined depth, the Sylphon bellows 62 will fold or collapse. In FIG. l, this depth is indicated as being roughly 30 feet, which is an arbitrary value. The ratchet mechanism will accordingly permit the ratchet wheel 7 8 to index one step. This action, obviously, has no elect on the vehicle, which continues its glide. The operating cycle is initiated, a gliding descent restarted, and `the cycle repeated until such time as the ratchet on the vent mechanism 24 indexes to the high cam on the ratchet wheel 78. On the cycle where this occurs, the Sylphon bellows 62 will be unable to open the vent valve 54 upon reaching -the preselected depth on the ascending glide; and, the vehicle will surface for recovery.

Referring now to FIG. 7 wherein the gas release valve mechanism 26 is illustrated, it will be observed that this valve is interposed between lines 88 and 90 that are properly attached to provide communication between the gas reservoir 28 and the hull chamber 22. Thus, a Sylphon bellows 92 normally in an expanded or unfolded position has projecting therefrom a longitudinally extending spindle or stem 94 connected to a valve plug or piston 96. This plug 96 includes a concentrically mounted sleeve or bushing 98, substantially as illustrated. In addition, a transversely extending valve plug port 100 is suitably attached to ultimately be aligned with both the passage 88 and 90 at selected times during its glide cycle. A ven-t 102 is conveniently tapped into the opening behind plug 96 for the usual purpose of facilitating the desired piston action.

When the glide of the craft 20 has proceeded to a depth such that the hydrostatic force of the sea pressure causes the Sylphon bellows 92 in the gas release mechanism 26 to collapse, the valve plug port 100 will eventually align with the lines 88 and 90. At such time, gas from the pressure reservoir or bottle 28 is introduced into the water ballast compartment 22; and, this gas will be unable to escape since the vent 54 to the compartment 22 was closed earlier as the vehicle submerged downward past the actuation depth. Consequently, water ballast is forced from the Vehicle through the venturi 30. Discharge of the ballast, naturally, will result in an increase of speed by an impulse elfect caused by Ithe release of ballast with a resultant pitch-up of the craft 20 from the glide path. As the water ballast continues to be expelled, the pitch-up tendency generated by the ballast release, together with the decrease of negative buoyancy gradually causes the vehicle to start a controlled glide toward the surface. When the vehicle passes the point in its ascent that caused the gas release valve 26 to open during descent, the gas release valve will once again close. Beyond this point in ascent, ballast Water will be discharged by the expansion of the entrapped gas in the vehicle 20 as the hydrostatic depth pressure decreases during the glide toward the surface.

The vehicle 20 is initially prepared for launching by removing the high-pressure gas reservoir 28, which may be in the form of a commercially available bottle, and charging it with a suitable high-pressure gas. In this connection, nitrogen gas at approximately 1850 p.s.i. should work satisfactorily under most circumstances. The gas bottle 28 is then suitably installed and properly connected with the gas release valve 26. The selected actuating means for this valve 26, as well as the vent mechanism 24, are preset for purposes of changing the craft buoyancy at the desired times and/ or upon encountering selected conditions. As for example, the programmed underwater course can be controlled by an actuating means 31 including a switch operable on a timer principle or responsive to underwater pressures, depths or other underwater conditions.

In the disclosed embodiment herein, the control means for the vent mechanism 24 and gas release valve 26 are exposed to water pressures and are set for a selected number of operating cycles. The payload or desired instrumentation 35 for accompanying the desired objectives and missions is then checked. The glider 20 is now ready for launching.

An acceptable method of launching is to slide the vehicle 20 down a ramp (not shown) attached to a surfacekeeping mother vessel (not shown). This ramp may have as shallow an angle of incline as possible to minimize water entry impact. Obviously, the ramp is pointed in the desired direction of transit, and the vehicle 20 is released. When the vehicle 20 enters the water, the vent mechanism 24 is open; and, consequently, the air entrained within the chamber 22 is allowed to escape. This air is replaced with sea water; and, under such circumstances, the vehicle 20 becomes negatively buoyant. Hydrodynamic forces then cause the glider 20 to proceed toward the bottom of the body of water in a controlled manner at a determinable velocity along a prescribed path. The glider 20 continues to a predetermined depth, at which the vent mechanism 24 closes. As will be more fully understood shortly, this action has no effect on the vehicle 20 which continues its glide pattern in a downward direction.

When the desired depth has been reached or condition encountered, gas will be permitted to escape from the reservoir 28 and be introduced into the water ballast compartment 22. As this gas is introduced into the water compartment 22, it is unable to escape since the vent mechanism 24 is closed. Consequently, water ballast is forced from the vehicle 20 through the venturi 30. Discharge of the ballast causes an increase of speed by the obvious impulse effect of the ballast release, which results in a pitch upwardly from the glide path. As the water ballast continues to be expelled, this tendency generated by the ballast release, together with the decrease of negative buoyancy, gradually causes the vehicle 20 to start a glide toward the surface. When the vehicle 20 passes the predetermined point in its ascent or, more specifically, the actuation depth of the gas release valve 26, this valve will close. In removing ballast, water will be discharged by the expansion of the trapped gas in the vehicle 20 as the hydrostatic depth pressure `decreases during the glide toward the surface.

The glider 20 will continue its glide to the surface until the preselected depth, explained in the following, is

reached, at which time the vent mechanism 24 will open allowing the trapped gas to escape. Ballast flooding will occur, and the vehicle 20 will become negatively buoyant. A gliding descent will start, and the cycle of operation depicted in FIG. 1 will repeat until such time as the control of the vent mechanism 24 indexes upon the attainment of the selected cycle. When this occurs, the vent mechanism 24 will be prevented from opening upon reaching the selected depth on the ascending glide; and, accordingly, the vehicle 20 will surface for recovery.

The craft 20 is restrained in its descending glide path by the force of gravity opposed by the lift of the foils. If the vehicle 20 -is to conduct the same ascending glide, it is necessary to reverse the foils such that the lift of the foils opposes the upward force of buoyancy created gas generation within the hull 32. In FIG. 8, a foil 144 is illustrated and may correspond in length to the overall or combined length of previously described foils 44 and 46. In this connection, it is contemplated that the eX- po-sed sectors of foil 144 equals that lof foils 44 and 46 and may be of internal construction such that the foil reversal mechanism 146 need not reverse separate foil units projecting laterally from the vehicle hull 32.

A foil 144 may be employed which is symmetrically about the chord perpendicular bisector so that the foil may simply be rotated to achieve the desired effects by mechanism 146. If the foil 144 is rotated 180 in the plane of FIG. 8, the desired effect of reversing lift without changing lift magnitude will have been achieved. The method chosen to achieve this is through the action of a bellows 148 having an internal spring 150 and which advantageously responds to changes of hydrostatic pressure. In addition, the reversal mechanism 144 may include a rack 152, the teeth of which are adapted to mesh with those of pinion 154 rigidly mounted with respect to the foil 144. The gear rack 152 contains stops 156 and 158 having beveled cam faces 160 and 162, respectively, that are adapted to cam with complementary-shaped faces on projections 164 and 166 forming extensions of the respective bellows 168 and 170. The rack 152 includes a reduced extension 172 which cooperates in providing a pair of shoulders 174 and 176, which are adapted to engage surfaces of a stop plate 178 extended from the hull 32.

The arrangement of parts in FIG. 8 represents their ordinary disposition at the time of launching. The bellows 148, 168 and 170 are in an extended position and the foil 144 restrained from movement by the position of the gear rack 152 to which shoulder 174 cooperates with plate 178 to form one stop; and, the spindle 164 of bellows 168 is adapted to engage with projection 156, as shown, to form another stop. As the vehicle 20 submerges, the bellows 148, 168 and 170 start to compress or collapse. However, bellows 148 is restrained, because the rack 152 is latched as a result of the engagement of associated surfaces of spindle 164 and projection 156. When the proper depth for foil reversal is reached, bellows 168 is retracted sufficiently to clear spindle 164 from projection 156, with the result that bellows 148 is now permitted to collapse against the bias of the internal spring 150. The spindle 166 will cam against projection 162 and become latched therewith. Obviously, if bellows 148 withdraws or displaces rack 152, the foil 144 is advantageously rotated approximately 180. To insure this relative position, the spindle 166 cooperates with projection 158, while, at the same time, shoulder 176 becomes associated with stop plate 178.

The vehicle 20 is now in a position to initiate a gliding ascent toward the water surface. Under such circumstances, lthe bellows 148, 168 and 170 will expand, with the result that the bellows 148 will load the rack 152 against the spindle 166 of bellows 170. At such predetermined depth as bellows 17 0 expands suiciently, the rack 152 will be released; and, the spring of bellows 148 will force the parts to assume their respective positions 7 depicted in FIG. 8. The motion of the rack 152, accordingly, reverses the foil 144, thereby preparing the glider 20 for a gliding decent and another operating cycle.

The present invention contemplates the retraction of foils and, at the same time, projection or spreading of a new set of foils for purposes of changing the hydrodynamic characteristics of the glider. In this connection, reference is made to FIG. 9, in which a pinion 200 is adapted to be rotated in response lto predetermined depths in a manner similar to that previously described in connection with the rotation of pinion 154 and illustrated in FIG. 8. As will be observed, the pinion 200 is meshed with gears 202 and 204 xed to the composite wing or foil units 206 and 208, respectively. In accordance with a contemplated embodiment, each of the foil units 206 and 208 may include a short span high camber foil 210 and 212, respectively. On the other hand, the respective foils 214 and 216 may possess a longer span and different camber, if desired. Thus, when foils 210 and 212 are retracted or Withdrawn within hull 232, which, in most material respects, resembles the hulls previously described herein, foils 214 and 216 are projected transversely as shown. In this connection, by simply rotating pinion 200 counterclockwise in the plane of FIG. 9, the foils 214 and 216 will be retracted and the foils 210 and 212 projected.

In FIG. 10, it will be observed that provisions herein are made for a change in the dihedral of the foils relied upon for hydrodynamic lift. Thus, in accordance with the teachings of the embodiment illustrated in FIG. 9, foils 314 and 316, corresponding to the foils 214 and 216, may possess a dihedral suitable for glider decent; whereas, foils 310 `and 312, corresponding to foils 210 and 212, may define a greater dihedral suitable for glider ascent.

Thus, in view of the teachings provided by the embodiments illustrated in FIGS. 8, 9 and 10, it should be clear that foil configuration `and area, incidence angle, and aspect ratio can be selected and varied depending on the desired glide path characteristics, such as glide angle and speed.

With respect to FIG. 11, it should be understood that the present invention contemplates a method of recovery for the above embodiments of underwater craft. A lightweight plastic sphere 400 may be conveniently loaded in the hull, as for example, at the nose thereof in folded condition to be ultimately expanded to a sphere of proper proportions. A light-weight mesh 402 of suitable material is properly placed around the plastic material and is adapted to be decended to approximately the same size as the sphere.

When the glider 20 reaches the water surface after traversing a programmed course, a relatively small cartridge (now shown) of compressed gas inates the sphere 400 which, in turn, supports the light-weight mesh. In this connection, an ejection means (not shown) in the form of a spring can be employed for purposes of releasing the folded sphere 400 from the nose of the glider. Since suitable ejection means and gas cartridge are employed in connection with many life preservers and floats, they have not been disclosed in detail. Both the cartridge and ejection means can be actuated by a bellows or other suitable devices responsive to the approach of the water surface or actual surfacing of the submerged craft.

As will be evident, the light-weight mesh 402 is attached to a pendant 404 which, in turn, is secured to the glider 20, as shown. Upon nearing the site of the surfaced craft, a line-throwing gun with a barged spindle 406 and connecting line 408 is shot at the inflated balloon 400. Naturally upon contact, the spindle 406 will deflate the balloon and intermesh with the similarly collapsed lightweight mesh 402. The line 408 may then be retracted and the glider recovered by the mother vessel.

In view of the foregoing, it will be apparent that the underwater craft can be located visually or by beacons (radio, sonar, radar or other) and recovery effected. Obviously, the methods of recovery will vary with the means of the recovery vessel. It may be recovered by nets, grappling systems, baskets or a variety of wellknown methods for bringing objects aboard surface vessels.

Although directivity has not been described in detail, it should be understood that conventional steering means, such as directional gyro steering systems, are con-templated and may be readily adapted to this invention. The well-known angle control system can be employed and may be of the type that is governed by a potentiometer driven at a constant speed so that output characteristic is linear with respect to time. A particular glide angle will result in one and only one particular rate of change of depth for a xed vehicle speed. Pressure measured in weight per unit area is directly and linearly related to depth. It is therefore possible to drive a linear output potentiometer with uniform motion such that the variable voltage delivered by the potentiometer will be a function of the rate of change of depth as would be generated in a constant angle glide. Such a device would then establish a reference or standard against which the actual glide angle may be compared to determine whether the actual glide angle is conforming with the desired glide angle. This measurement and comparison is achieved by utilizing a pressure transducer which measures actual depth and delivers an electrical Voltage which is proportional to the measured depth of the vehicle at any particular time. It may be seen readily that if the voltage output of the reference or standard is compared to the voltage of the measuring device, that a difference in these voltages will indicate that the vehicle is not conforming with the desired glide angle. Well known electrical differentiating devices may be used to constantly compare the standard voltage to the measured voltage to determine the magnitude and direction (higher or lower) of glide path error. r[his error signal may then be applied to correct lthe glide path.

Although a substantial number of the contemplated and somewhat preferred gliders 20 will not be manned and also will not necessarily be of sufficient size to conveniently house an individual or crew, the present invention is, nevertheless, applicable thereto. Thus, selective manual steering or use of a gyro steering system for the craft through its rudder is possible. It should be clear that an isolated and pressurized compartment with suitable air supply will be present inthe hull.

The gas generator or reservoir 28 may include liquid, solid or hybrid fuel (e.g. hydrogen peroxide and diesel fuel or inhibited red fuming nitric acid and turpentine, etc.). These gas generators will be regulated to maintain a constant gas pressure in the pressure container and will provide this pressure directly to a gas release valve similar to valve 26. As the gases provided by the generator tend to become absorbed by the ballast water with increases in operating depth requirement, a piston and cylinder arrangement could be provided in the discharge line from the gas release valve. The piston and cylinder will serve to prevent the gas from the generator from coming into contact directly with the ballast water until an upward ascent has been instituted. As very deep operating depth requirements evidence themselves, the gas generator system can be changed to a cartridge or squib arrangement, which will fire at a particular depth and generate sucient gas to drive a piston causing the buoyancy to go positive. This arrangement will permit temporary isolation of the gas from the ballast water for not only preventing absorbtion, but also preventing cooling and attendant condensing with Volume reduction.

The hydrodynamic glider, naturally, is propelled only by buoyancy forces acting upon the hydro foils. Upon launching, the hydro glider is negatively buoyant and glides to some preselected depth, which can be as much as 1000 feet or more. When the preselected depth is attained, a gas generator provides suicient gas to cause the glider buoyancy to become positive. The accompanying reversal of forces causes a gliding ascent to occur, which continues to the surface.

The foregoing provides for an effective system for rapid data acquisition which is economical, reliable and relatively fast. The hydrodynamic glider disclosed herein is capable of carrying instrumentation payload which will permit acquiring data at rates and magnitudes heretofore prohibitively expensive, not to mention the comparative superiority and accuracy of the means, as well as the end results.

Naturally, many of the elements and components constituting the payload and instrumentation 35 can be of a low order of sophistication because of the lower frequency response required in oceanography. Marine life and phenomena can be eiectively studied and data pertaining thereto similarly obtained. The craft herein disclosed can bear photographic and similar equipment for such purposes, as well as suitable equipment for recovery of the material products of the sea.

Thus, the aforementioned objects and advantages are most effectively attained. This invention is in no sense limited by the specific embodiments disclosed herein; and, accordingly, its scope is to be determined by the appended claims.

What We claim is:

1. An underwater glider propelled forwardly by a change in its buoyancy comprising a hull defining a ballast compartment, foils projecting transversely from said hull for cooperating to have hydro-dynamic lift forces imposed upon said foils, stabilizing means on said hull for `stabilizing the glide path of said glider underwater, ballast changing means including a gas reservoir within said hull for changing the buoyancy of said glider by changing the ballast Within said ballast compartment, actuating means on said glider lfor operating the ballast changing means in response to a selected parameter, control means being actuated by said actuating means for releasing the gas within said reservoir in said ballast compartment for causing said glider to ascend, a further control means also being actuated by said actuating means for permitting the intake of ballast water to cause said glider to descend and a venturi being provided on said glider for providing a discharge passage for the ballast water when the gas in the compartment is released.

2. An underwater glider propelled forwardly by a change in its buoyancy comprising a hull defining a ballast compartment, foils projecting transversely from said hull for cooperating to have hydro-dynamic lift forces imposed upon said foils, stabilizing means on said hull for stabilizing the glide path of said glider underwater, ballast changing means within said hull for changing the buoyancy of said glider by changing the ballast within said ballast compartment, control means for actuating the ballast changing means to cause the glider to ascend, further control means for permitting the intake of ballast water to cause said glider to descend, a discharge port means provided on said glider for providing a discharge passage for the ballast water, and means for automatically displacing said foils at the maximum and minimum depths during ascent and descent so that the forces of hydrodynamic lift imposed upon said glider can be regulated so that the underwater movements of said glider can be confined to a predetermined path.

3. The invention in accordance with claim 2 wherein a pressure sensitive device set to respond upon the attainment of a predetermined depth under water by said glider is operatively connected with at least one of said control means for actuation thereof upon the attainment of the predetermined depth under Water by said glider.

4. The invention in accordance with claim 2 wherein timing means are provided on said glider for determing the extent to which said glider remains submerged.

5. The invention in accordance with claim 2 wherein actuating means are provided on said glider and include independent mechanisms for actuating both of the control means independent of one another.

6. The invention in accordance with claim 2 wherein said glider further includes recovery means for enabling said glider to be recovered upon completion of a programmed glide under water.

7. The invention in accordance with claim 6 wherein said recovery means includes an inflatable balloon, a mesh surrounding said balloon, and means for attaching said balloon and mesh to said glider.

8. The invention in accordance with claim 2 wherein the foil displacing means include means on said glider for presenting one foil dihedral during glider ascent and another foil dihedral during glider descent so that the forces of hydro-dynamic lift imposed upon said glider during glider ascent and descent can be regulated so that the underwater movements rof said glider can be confined to predetermined path.

9. The invention in accordance with claim 2 wherein the foil displacing means include means on said glider for presenting one foil angle of incidence during glider ascent and another foil angle of incidence during glider descent so that the forces of hydro-dynamic lift imposed upon said glider during glider ascent and descent can be regulated so that the underwater movements of said glider can be confined to a predetermined path.

10. An underwater glider propelled forwardly by a change in its buoyancy comprising a hull delining ballast compartment, foils projecting transversely from said hull for cooperating to have hydro-dynamic lift forces imposed upon said foils, stabilizing means on said hull for stabilizing the glide path of said glider underwater, ballast changing means within said hull for changing the buoyancy of said glider by changing the ballast within said ballast compartment, said ballast changing means including a source of gas, control means for releasing the gas from said source in said ballast compartment for causing the glider to ascend, further control means for permitting the intake of ballast Water to cause said glider to descend, a discharge port means provided on said glider for providing a discharge passage for the ballast Water when the gas is released, and means for presenting one foil dihedral during glider ascent and another foil dihedral during glider descent so that the forces of hydrodynamic lift imposed upon said glider during glider ascent and descent can be regulated so that the underwater movemerlts of said glider can be conned-to a predetermined pat 11. An underwater glider propelled forwardly by a change in its buoyancy comprising a hull defining a ballast compartment, foils projecting transversely from said hull for cooperating to have hydro-dynamic lift forces imposed upon said foils, stabilizing means on said hull for stabilizing the glide path of said glider underwater, ballast changing means within said hull for changing the buoyancy of said glider by changing the ballast Within said ballast compartment, said ballast changing means including a source of gas, control means for releasing the gas from said source in said ballast compartment for causing the glider to ascend, further control means for permitting the intake of ballast water to cause said glider to descend, a discharge port means provided on said glider for providing a discharge passage for the ballast water when the gas is released, and means for presenting one foil angle of incidence during glider ascent and another foil angle of incidence during glider descent so that the forces of hydro-dynamic lift imposed upon said glider during glider ascent and descent can be regulated so that the underwater movements of said glider can be confined to a predetermined path.

(References on following page) References Cited by the Examiner UNITED STATES PATENTS Leon 114-25 X Lagergren 114-16 White 11S-4 Yancey 46-94 Ardo 244--49 Bonney 244-47 Dray 114-54 Zukor 244-77 Daly 114-25 X Boady 114-54 X Doolittle 114-16 X Downs.

1 2 Fitzpatrick 114-16 X Gongwer 114-16 Presnell 114-16 Vine 1 14-1 6 Ruiz 46-94 FOREIGN PATENTS Great Britain. Great Britain. Great Britain. Italy.

MILTON BUCHLER, Primary Examiner. 

1. AN UNDERWATER GLIDER PROPELLED FORWARDLY BY A CHANGE IN ITS BYOYANCY COMPRISING A HULL DEFINING A BALLAST COMPARTMENT, FOILS PROJECTING TRANSVERSELY FROM SAID HULL FOR COOPERATING TO HAVE HYDRO-DYNAMIC LIFT FORCES IMPOSED UPON SAID FOILS, STABILIZING MEANS ON SAID HULL FOR STABILIZING THE GLID PATH OF SAID GLIDER UNDERWATER, BALLAST CHANGING MEANS INCLUDING A GAS RESERVOIR WITHIN SAID HULL FOR CHANGING THE BYOYANCY OF SAID GLIDER BY CHANGING THE BALLAST WITH SAID BALLAST COMPATMENT, ACTUATING MEANS ON SAID GLIDER FOR OPERATING THE BALLAST CHANGING MEANS IN RESPONSE TO A SELECTED PARAMETER, CONTROL MEANS 